A model of a B-Double flatbed trailer to go with my custom Peterbilt 379. As with all my models it is in scale 1:17,5. It features PF, lights, remotely operated landing gear, remotely operated fifth wheel on first trailer and solid axle suspension on all axles.

About this creation

As with many more trailer types I've always been intrigued by B-Double trailers. This type of trailer is also referred to as B-Train or Super-B. I am not sure but if I'm correct this depends on the country or US state this type of trailer is used.
With the limitation that came with my Trailer 2 (Drop Deck) I was unable to build a trailer with a fifth wheel as the first or leading trailer of this B-Double has. Basically because the suspension was poor and the frame needed to drop. Due to this all things would be at different heights as it would be on the truck and that is not what I wanted. Again I want trucks and trailer to be interchangeable so things had to be right.

Since I have improved my building skills this Trailer 5 (Flatbed) brought me so many new possibilities. No longer a drop deck, but a straight flatbed which was the base for this latest creation. Not that I am not OK with drop decks cause I am OK, but back then I basically had no choice and now I do. I was unable to build a trailer strong enough and all things at the right height without the dropped deck and frame.

Like I mentioned above I am always improving my skills and models and the same goes for this B-Double. On the outside it might just look the same as Trailer 5 (Flatbed) but be sure it isn't. With every new truck and/or trailer something has been improved. Some times I think more of myself as an engineer who is improving stuff rather then coming up with new things. Even though I do come up with new things quite a lot I have to admit that the process is quite heavy. Improving stuff is much easier and I have loads of fun with it too so why bother.

Both previous flatbed trailers had a deck that rests directly on the trailers chassis. Even though this is not odd, since all real life flatbed trailers are build this way, I had to change this concept. Difficult to explain why exactly but this all had to do with the way I build the trucks and the different approach I have with trailers. To over come this gap I had to raise the deck of the trailer just a little. It is because of this I managed to give the first trailers rear part of the frame the exact same dimensions and specifications as the the trucks frame. To be short, the trucks rear end as well as the leading trailers rear end are equal, exact same frame hight, same fifth wheel hight, same suspension travel and so on.

Another major improvement on this model came with the introduction of this new LEGO Power Functions Battery Box a couple of years ago. The one that holds 6 AAA-batteries which is so much smaller and I am very happy The LEGO Group came with this amazing new part. In opposite to my other flatbed trailers I no longer had to install the battery box at the very rear end of the trailer. This new type of battery box can be located next to the trailers frame to simulate for example a toolbox. With this I was able to get the wheels all the way to the rear and of the frame. First of all this gave me the opportunity to give the leading trailer its fifth wheel, but also was I able to create a much shorter trailer, the second one.

One great new feature on this US Truck 9 (winch truck) model I build a couple of years ago was the remotely operated fifth wheel. With this new feature coupling and uncoupling the trailer could be done without any manual actions. All is done with the remote control and that is really great fun to me, this is what I do so to speak. Ever since I started thinking about building this new trailer I wanted to give it a remotely operated fifth wheel too. So I did and with this the entire truck and trailer(s) are operated remotely.

My previous flatbed trailers where already equipped with a remotely operated landing gear, but this new trailer has an improved version of it. Again both landing gear and parking break are operated at the same time, both powered using a single PF M motor. Both landing gear and parking break had to be aligned on both previous trailers. With this I mean as soon as the landing gear rests on the service the parking break had to be on. A major disadvantage of this system is that if the trucks fifth wheel is a little higher or lower this system fails. What this system needs is an adjustable landing gear.

The parking break is driven by a double Technic 24 tooth clutch gear powered by a worm gear. On both previous flatbeds this was a single Technic 24 tooth gear (without the clutch) powered by a worm gear. The parking break is activated while the landing gear is still lowering. With this system the trailers height could easily be adjusted to the trucks fifth wheel. Because of the clutch gears the parking break system is not over stressed. I started out with a single clutch gear, but that was not strong enough. Of course this system is installed on both leading and second trailer.

Quoting Carlos Desilva
OMG your MOCs are amazing. Too bad you don't have instructions. :( The suspension techniques are remarkable. The fifth wheel idea? WHAT???(in an awesome sounding way) And you certainly have an eye for design. I take my hat off to you sir.

this is the best moc truck ever. the fact that it's so functional is simply mind-boggeling. the way you can attach and detach trailers is outta-this-world. this is one of my favorite models EVER and deserves to be more popular.

Quoting Carlos Desilva
OMG your MOCs are amazing. Too bad you don't have instructions. :( The suspension techniques are remarkable. The fifth wheel idea? WHAT???(in an awesome sounding way) And you certainly have an eye for design. I take my hat off to you sir.

That are very kind words and I thank you for that. It took me about two years to get the suspenion and all going. The fifth wheel was another story to be honest. I just sat down one evening and started thinking and experimenting with parts. Withing two hours I managed to finish it and it never changed since. Only the remotely operated release was added two years later...

OMG your MOCs are amazing. Too bad you don't have instructions. :( The suspension techniques are remarkable. The fifth wheel idea? WHAT???(in an awesome sounding way) And you certainly have an eye for design. I take my hat off to you sir.

Cool combo! The colors look very nice for this truck. I really like your attention to detail, right down to the motorized landing gear, reflective tape, and the working lights. It's all wonderful. I always like to look at your trucks, and see what new thing you've come up with.

Quoting peter smyth
Another fantastic MOC that we all wish we could build!!

Blush... :-) That is so kind of you...

Quoting John Daniels
Wow this is amazing! The fifth wheel design is awesome. The color scheme is cool to.

Thanks so much. The 5th wheel design is quite "simple". I tried to catch the looks and the feels of the real thing but with great LEGO functionality...

Quoting Brett Ryan
Great work mate! I really like the improvement that you've made with the landing gear, something which I have been thinking about myself.
As usual, you've produced another top notch example.

Well, thanks, so kind of you. The first landing gear design was nice, but not flexible. With this new design the trailer could be lowered or raised to adjust to the trucks fifth wheel height like in real life...